Viruses exploit host cell transcription and translation to allow the exclusive or predominant expression of viral genomes, MRNAS and proteins. An unusual insect virus, the Campoletis sonorensis polydnavirus regulates insect immune, growth, and developmental systems. The major objective of this proposal is to identify the viral genes and describe the functional activities of the gene products that suppress insect immunity, growth and development. Available evidence suggests that the polydnavirus may contribute to the survival of the wasp by altering the translational capabilities of the parasitized insect leading directly to the deleterious effects associated with parasitization. Identification and study of specific proteins that modify host cell translation could provide entry into the viral regulation of insect immune, growth and developmental systems and facilitate the development of a new set of experimental reagents to study the regulation of certain insect physiological systems. Studies of the mechanisms allowing viruses to regulate cellular processes have contributed to the basic knowledge of RNA transcription, translation, protein processing and trafficking and are likely to contribute to our molecular understanding of insect physiological systems. A better understanding of insect immunity may contribute to selection of strains of important insect vectors that are unable to transmit disease or allow targeting of the insect immune system to increase the susceptibility of selected insect species to disease. As vectors of many important human parasites and as our major competitors for food, a more complete understanding of insect growth, development and immunity is likely to improve our nation's health.